It is possible that room mailboxes have their default permissions set to show only availability, but sometimes you may want to allow users to see what has been booked (title of the meeting). You can either set this through Outlook but this is tedious as you'll need full mailbox access for this to work. However, admins can also set this via Powershell (for M365, load the Exchange Online module).

To view the current permissions:

Get-MailboxFolderPermission my-meeting-room:\calendar

To set the permissions to show limited details by default:

Set-MailboxFolderPermission -AccessRights LimitedDetails -Identity my-meeting-room:\calendar -User default

Optionally, if you wish to know who booked the meeting, you can set the room to add this to the subject of every meeting:

Set-CalendarProcessing -Identity my-meeting-room -AddOrganizerToSubject $true -DeleteComments $false -DeleteSubject $false